Variable range vlookup

[montex01]

Please help, I'm stuck with a variable rang vlookup between (2) worksheets.

The vlookup is in worksheet 1 and worksheet 2 is where the range is not constant. It randomly starts in the row 1000 (right now it starts on row 1356). How do I set up a variable range on worksheet 2 and then do a vlookup.

This is what I have so far:

Sub Test()
'''Identify Unattributed in the UNFI Natural file

    Dim mRange As String
    Dim mRow As Long, lr As Long
    Dim mOriginal As String
    
    Dim mEcallunattributed As String
    Dim mUNFI As String
    
    Dim mTempRow As Long
    Dim mNewStart As Long

    Dim wba As Workbook
    Set wba = ActiveWorkbook
    
    mEcallunattributed = "UnattributedReport_All Items.xlsx"


'Worsheet 1 already opened
    wba.Activate
    
 'Open worksheet 2
     Workbooks.Open Filename:=mUnattributed, ReadOnly:=True

'Find the range
    Range("B2").End(xlDown).Select
    ActiveCell.Offset(4, 0).Select

 'The range is the 2nd part of the worksheet. There is 2 spaces between the top data and the bottom data (bootm data is range I'm trying to create on the variable range on)
    Selection.End(xlDown).Select
    mRow = Selection.Row
    mRange = "B" & mRow
    
'Go back to worksheet 1 for vlookup    
    wba.Activate

    Range("L3").Select
    mRange = "L" & mNewStart & ":" & "L" & mRow
    Range(mRange).Select
    mValue = "=VLOOKUP(D:D,'[UnAttributed_Nielsen List.xlsx]Wks Items'!C:C,1,0)"
    Selection.Value = mValue
    Selection.Copy
    Selection.PasteSpecial Paste:=xlPasteValues

End Sub